UltraViolet, a women’s rights advocacy group, published this video about abortion myths, and cited a series of statistics about women’s access to abortion. One statistic piqued our curiosity: one in three women will have an abortion by age 45. This is a ubiquitous statistic, and an abortion rights campaign is even named after the figure.

What are the underlying data, and are there any important caveats?

The Facts

The figure comes from a 2011 study by Guttmacher Institute, a reproductive health research organization, tracking changes in abortion rates and estimating the lifetime incidence of abortion among women of reproductive age. The purpose was to update 1992 estimates that 43 percent of women of reproductive age would have an abortion by age 45. The abortion rate had declined since 1992, and researchers hypothesized that the proportion of women who will have an abortion during their lifetime also probably declined since then.

The study used abortion rates (the number of abortions per 1,000 women) for subgroups of women (including age, socioeconomic status, race and ethnicity) who responded to the Guttmacher Institute’s 2008 Abortion Patient Survey of nearly 9,500 women.

Researchers used survey data to find the first abortion rate for age subgroups, multiplied the rate by the number of years in each age group, and added up the number of first-time abortions that had taken place by the time women were 45 years old. This was called the “cumulative first abortion rate,” through which they came up with the “lifetime incidence” of abortion, or the “one in three” figure.

Researchers found that the proportion of women expected to have an abortion by 45 decreased from 43 percent in 1992 to 30 percent in 2008, and this decline paralleled the decline in abortion rates during that period. While the number of abortions decreased among most subgroups of women except women who were poor, cohabiting, ages 20 to 24 or non-Hispanic African Americans.

That means 30 percent of women (effectively, one in three) will have an abortion by age 45, if the 2008 abortion rate prevailed.

But that rate did not prevail. Guttmacher Institute found the abortion rate for women ages 15 to 44 dropped by 13 percent between 2008 and 2011. To the Guttmacher Institute’s credit, it usually adds the caveat that the figure is based in the 2008 abortion rate.

Rachel Jones, Guttmacher Institute’s principal research scientist who conducted the abortion rate and lifetime incidence studies, said it’s “quite possible” that the “one in three” statistic has changed because of the decline in abortion rate since 2008. (Studies show the abortion rate declined further between 2011 and 2013.) But it’s impossible to predict whether the lifetime incidence statistic would increase or decrease, because it depends on how the number of women having first-time abortions changed during that period.

Guttmacher Institute is now analyzing 2014 Abortion Patient Survey results from more than 8,000 women. This survey is done every six to eight years, and this is the first update since 2008. An updated figure for the “one in three” lifetime incidence will not be available until early 2017, Jones said.

“I’m reluctant to say it will probably go down. It’s certainly possible,” Jones said. “The abortion rate was going down from 1992 to 2008, and we saw a substantial decline from lifetime incidence of abortion. Intuitively, we would see a decline … based on past patterns. But again, it’s a little more complicated than that, and so I can’t make any predictions.”

In 2008, about half of abortion patients had had their first abortion (more than half of women ages 25 and older had had an abortion). If fewer women who had abortions in 2014 have had a prior abortion, this could potentially result in a higher lifetime incidence, Jones said.

Teen birth, teen pregnancy and teen abortion rates also have declined since 2008. If most of the abortion rate decline is due substantially to declining teen abortions, it may not have much effect on the overall lifetime incidence, Jones said. If large numbers of teens had abortions after they aged out of the 15-19 range, the lifetime incidence would not change by much.

Among the potential reasons for the abortion rate decline is that more women are using highly effective contraceptive methods, like intrauterine devices (IUDs) that are implanted and decrease the risk of user error.

In recent years, some states imposed new restrictions on abortions. Plus, the Affordable Care Act went into effect in January 2014, expanding women’s access to preventive care (including contraception). These changes could also contribute to the abortion rate, but there are not enough data to draw definitive conclusions, Jones said.

Nita Chaudhary, co-founder of UltraViolet, said in a statement that the “one in three” figure shows that abortion is “part of everyday life.”

“It’s time to end the shame and stigma around people who support or exercise their abortion rights and go on offense. We need to support women’s rights to have full and productive lives, and make their own decisions about what’s right for their health and their families,” Chaudhary said. “Whether the Guttmacher Institute figures go slightly up or down, what doesn’t change is the stigma associated with abortion and the impact it has on those who decide to have one.”

The Pinocchio Test

The Guttmacher Institute, which came up with the statistic, calculated the “one in three” estimate based on 2008 abortion rates. If the same rate prevailed, the estimate would still be applicable. The organization is now coming up with a new calculation. Without the breakdown of first-time abortions of women ages 15 to 44 in 2014, we can’t definitively say whether this statistic would increase or decrease, or by how much — though previous trends indicate it could decrease. Guttmacher Institute tends to include the caveat in most references, but not always — such as the graphic that UltraViolet used as a source for its video.

Organizations, such as UltraViolet, repeating this figure need to include this caveat in their materials. This statistic is widely cited. At The Fact Checker, we have been critical of politicians and organizations citing data without doing enough due diligence to understand how old the statistics are. The “one in three” figure was an estimate based on the 2008 abortion rate, which has gone down since then.

The decline in abortion rates from 1992 to 2008 saw a parallel decline in the proportion of women expected to have an abortion by 45. We don’t know yet if the 2014 data, which is being calculated right now, will show the same trend. But until early 2017, when Guttmacher Institute plans to release the updated findings, this “one in three” figure should be treated with caution and always accompanied by the appropriate caveat.